NorthStar GM1708 961X Installation Manual

Also see for 961X: Reference manual Operation and reference manual

NorthStar GM1708 961X Installation Manual Manual pdf 52 page image

SECTION TWO - InstallationPage 42 961 INSTALLATION MANUAL Revision Ab. Testing the GPS portion of the splitter and a combo antenna: When using a combo antenna and split-ter, the splitter gets 7.75 VDC from the beacon receiver, and then feeds the combo pre-amp with thatsame voltage level. The splitter must have this 7.75 VDC supplied to the differential port in order forthe GPS and the differential signal to be passed through the splitter. To test the GPS portion of thecombo antenna, disconnect the splitter and plug the combo antenna directly into the GPS BNC con-nector (provided that the 5.5 VDC is present). This troubleshooting technique effectively eliminatesthe splitter from the equation. If the splitter is bad, GPS may not work when connected normally(provided that the 7.75 VDC from the beacon receiver is present). Note that the combo antennashould never be plugged directly into the GPS port under normal circumstances because the voltagefeeding the amplifier is too low and this will result in low GPS signal levels being sent to the GPSreceiver.c. The beacon receiver (8500) supplies the 7.75 VDC to the 8410 (in the case of a whip-type antennainstallation), or the splitter (in the case of a combo antenna installation), which in turn feeds thecombo antenna.Table 4: Troubleshooting the radar interfaceComponent Symptom Possible Solutions/Reasons961 CONTROL HEAD The display is either knocked outcompletely, or the screen flashesafter the radar is turned on (a whiteflash corresponds to each revolutionof the radar, when the radar range isset to 6 nm or above).• Stand directly in front of the display todetermine if the problem is related tointerference to the control head.• Put the radar into “standby” mode; if thedisplay still flashes, a non-radar type ofinterference is occurring.• Call the Northstar Service Departmentto determine if the necessary internalradar shielding has been installed. Ifyes, ensure that the 961 head (and pro-cessor) aren’t in the direct path of theradar aperture.• Ensure that there’s a maximum separa-tion between the 961 control head/pro-cessor and the radar cables. Wheneverpossible, run the cables of the radarand the 961 on opposite sides of thevessel.961 PROCESSOR The display is either knocked outcompletely, or the screen flashesafter the radar is turned on (a whiteflash corresponds to each revolutionof the radar, when the radar range isset to 6 nm or above).• Stand directly in front of the processorto determine if the problem is related tointerference to the processor.• Be sure that the processor is mountedas far away vertically from the radome.The best location for the processor isout of the weather, so try to mount it inthe salon or as low as possible.• Determine if the 961 processor has theRF-125 shielding modification installed(if you need assistance, call the North-star Service Department).